package com.change.study.security;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;

import sun.misc.BASE64Decoder;

public class RSAEncrypt {
	  private static final String DEFAULT_PUBLIC_KEY=  "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDe0vQcgnUqEOsdNe5OIkYdTRVL"+ "\r" 
				+ "JLCYNSca7+vIMF1PeFM84M3tL8I+pbrd0K1iRCQ9mk0aKsMaUkhrX7ZeCIziZcm0"+ "\r" 
				+ "tS364/dQ4eQBAm98M4pEj9Ijuwmhl4LbHDXJe/nh1wd7+ycDB9L2tkKJAybB0fP8"+ "\r" 
				+ "6cZTKvNXB46wo3lJzwIDAQAB"+ "\r" ;
		        
		    private static final String DEFAULT_PRIVATE_KEY=  "X8axF4fQHTbcPgwBcXFIjcBbmtbjuSfRluVXCtafOCoBoHSsGxgNlgHlKm4N/oSM"+ "\r" 
					+ "nz+7S1IU0V5Ya5okm3NaB4KotOWZ86w+sD2BCD0MK9zHVmEnNQIMumN6zFzAN5KJ"+ "\r" 
					+ "6mlQBh2n5lG/X+XmyPtBxlM5TRdPlH8CCmJU9TmEOZmVQTaYCUO/w9crjyH1YJ+O"+ "\r" 
					+ "d+J+zq73eaSy/8WJBIspIOxpRZA7V2qFFe2YgTot0I6zg9zIBUXwQ9bO7bQqfCL1"+ "\r" 
					+ "LHJh6A8Zua5EP63RRUE08bcWFbZO7OlBNeYitLN3NBKYGZjCxc0qBhIZPFBGlRyR"+ "\r" 
					+ "3WUxCBJdoVwEqINT0ZDi8VyZDYgNOq0YQv2/i4tQKLfgzUh0YJ5dkibFI3dzvusi"+ "\r" 
					+ "TyydcFJoPV+d3Vp/mFvnHd27GKr7aB9WRqSeULq+okDJpFVtx66YQJ/eUUu9JGrt"+ "\r" 
					+ "VZ9N4dpp8j+/0FcZN/FSLnLizHr6fxSC+N33sHorgui8sXqb6E3vdaABYk6xStDN"+ "\r" 
					+ "tOpFMC3v0G8tsRqHZdZabrkPBXczxY3j/qoexhHT7O+vCRL7g2QQHWkrJs9Hrb8H"+ "\r" 
					+ "60G/9B44l8qf7a5nYiblEYFJPsIgWEI5SSydFAE1sFxfaynhDIa1KbxtYAvsik6I"+ "\r" 
					+ "+iQkTAYR/mgosj6V8vH/Y2njkDYALT1FBE1nZCGXmdFPE9iJJ8HKuFMJMz35LOYf"+ "\r" 
					+ "FX0tin/IoV1MTnoGQ8hRbUMAeccjb2G+2fLqLoM3/3/7K1xCBVrOSF5jekxgfnaI"+ "\r" 
					+ "xx5rNoy6M0+Lj7DBqSwDfiTZL/2Af3osR8TxibmCDuffetYu2a63dg=="+ "\r" ;
		    
		    /**  
		     * 私钥  
		     */    
		    private RSAPrivateKey privateKey;    
		    
		    /**  
		     * 公钥  
		     */    
		    private RSAPublicKey publicKey;    
		        
		    /**  
		     * 字节数据转字符串专用集合  
		     */    
		    private static final char[] HEX_CHAR= {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};    
		        
		    
		    /**  
		     * 获取私钥  
		     * @return 当前的私钥对象  
		     */    
		    public RSAPrivateKey getPrivateKey() {    
		        return privateKey;    
		    }    
		    
		    /**  
		     * 获取公钥  
		     * @return 当前的公钥对象  
		     */    
		    public RSAPublicKey getPublicKey() {    
		        return publicKey;    
		    }    
		    
		    /**  
		     * 随机生成密钥对  
		     */    
		    public void genKeyPair(){    
		        KeyPairGenerator keyPairGen= null;    
		        try {    
		            keyPairGen= KeyPairGenerator.getInstance("RSA");    
		        } catch (NoSuchAlgorithmException e) {    
		            e.printStackTrace();    
		        }    
		        keyPairGen.initialize(1024, new SecureRandom());    
		        KeyPair keyPair= keyPairGen.generateKeyPair();    
		        this.privateKey= (RSAPrivateKey) keyPair.getPrivate();    
		        this.publicKey= (RSAPublicKey) keyPair.getPublic();    
		    }    
		    
		    /**  
		     * 从文件中输入流中加载公钥  
		     * @param in 公钥输入流  
		     * @throws Exception 加载公钥时产生的异常  
		     */    
		    public void loadPublicKey(InputStream in) throws Exception{    
		        try {    
		            BufferedReader br= new BufferedReader(new InputStreamReader(in));    
		            String readLine= null;    
		            StringBuilder sb= new StringBuilder();    
		            while((readLine= br.readLine())!=null){    
		                if(readLine.charAt(0)=='-'){    
		                    continue;    
		                }else{    
		                    sb.append(readLine);    
		                    sb.append('\r');    
		                }    
		            }    
		            loadPublicKey(sb.toString());    
		        } catch (IOException e) {    
		            throw new Exception("公钥数据流读取错误");    
		        } catch (NullPointerException e) {    
		            throw new Exception("公钥输入流为空");    
		        }    
		    }    
		    
		    
		    /**  
		     * 从字符串中加载公钥  
		     * @param publicKeyStr 公钥数据字符串  
		     * @throws Exception 加载公钥时产生的异常  
		     */    
		    public void loadPublicKey(String publicKeyStr) throws Exception{    
		        try {    
		            BASE64Decoder base64Decoder= new BASE64Decoder();    
		            byte[] buffer= base64Decoder.decodeBuffer(publicKeyStr);  
		            KeyFactory keyFactory= KeyFactory.getInstance("RSA");    
		            X509EncodedKeySpec keySpec= new X509EncodedKeySpec(buffer);    
		            this.publicKey= (RSAPublicKey) keyFactory.generatePublic(keySpec);    
		        } catch (NoSuchAlgorithmException e) {    
		            throw new Exception("无此算法");    
		        } catch (InvalidKeySpecException e) {    
		            throw new Exception("公钥非法");    
		        } catch (IOException e) {    
		            throw new Exception("公钥数据内容读取错误");    
		        } catch (NullPointerException e) {    
		            throw new Exception("公钥数据为空");    
		        }    
		    }    
		    
		    /**  
		     * 从文件中加载私钥  
		     * @param keyFileName 私钥文件名  
		     * @return 是否成功  
		     * @throws Exception   
		     */    
		    public void loadPrivateKey(InputStream in) throws Exception{    
		        try {    
		            BufferedReader br= new BufferedReader(new InputStreamReader(in));    
		            String readLine= null;    
		            StringBuilder sb= new StringBuilder();    
		            while((readLine= br.readLine())!=null){    
		                if(readLine.charAt(0)=='-'){    
		                    continue;    
		                }else{    
		                    sb.append(readLine);    
		                    sb.append('\r');    
		                }    
		            }    
		            loadPrivateKey(sb.toString());    
		        } catch (IOException e) {    
		            throw new Exception("私钥数据读取错误");    
		        } catch (NullPointerException e) {    
		            throw new Exception("私钥输入流为空");    
		        }    
		    }    
		    
		    public void loadPrivateKey(String privateKeyStr) throws Exception{    
		        try {    
		            BASE64Decoder base64Decoder= new BASE64Decoder();    
		            byte[] buffer= base64Decoder.decodeBuffer(privateKeyStr);    
		            PKCS8EncodedKeySpec keySpec= new PKCS8EncodedKeySpec(buffer);    
		            KeyFactory keyFactory= KeyFactory.getInstance("RSA");    
		            this.privateKey= (RSAPrivateKey) keyFactory.generatePrivate(keySpec);    
		        } catch (NoSuchAlgorithmException e) {    
		            throw new Exception("无此算法");    
		        } catch (InvalidKeySpecException e) {    
		            e.printStackTrace();  
		            throw new Exception("私钥非法");    
		        } catch (IOException e) {    
		            throw new Exception("私钥数据内容读取错误");    
		        } catch (NullPointerException e) {    
		            throw new Exception("私钥数据为空");    
		        }    
		    }    
		    
		    /**  
		     * 加密过程  
		     * @param publicKey 公钥  
		     * @param plainTextData 明文数据  
		     * @return  
		     * @throws Exception 加密过程中的异常信息  
		     */    
		    public byte[] encrypt(RSAPublicKey publicKey, byte[] plainTextData) throws Exception{    
		        if(publicKey== null){    
		            throw new Exception("加密公钥为空, 请设置");    
		        }    
		        Cipher cipher= null;    
		        try {    
		            cipher= Cipher.getInstance("RSA");//, new BouncyCastleProvider());    
		            cipher.init(Cipher.ENCRYPT_MODE, publicKey);    
		            byte[] output= cipher.doFinal(plainTextData);    
		            return output;    
		        } catch (NoSuchAlgorithmException e) {    
		            throw new Exception("无此加密算法");    
		        } catch (NoSuchPaddingException e) {    
		            e.printStackTrace();    
		            return null;    
		        }catch (InvalidKeyException e) {    
		            throw new Exception("加密公钥非法,请检查");    
		        } catch (IllegalBlockSizeException e) {    
		            throw new Exception("明文长度非法");    
		        } catch (BadPaddingException e) {    
		            throw new Exception("明文数据已损坏");    
		        }    
		    }    
		    
		    /**  
		     * 解密过程  
		     * @param privateKey 私钥  
		     * @param cipherData 密文数据  
		     * @return 明文  
		     * @throws Exception 解密过程中的异常信息  
		     */    
		    public byte[] decrypt(RSAPrivateKey privateKey, byte[] cipherData) throws Exception{    
		        if (privateKey== null){    
		            throw new Exception("解密私钥为空, 请设置");    
		        }    
		        Cipher cipher= null;    
		        try {    
		            cipher= Cipher.getInstance("RSA");//, new BouncyCastleProvider());    
		            cipher.init(Cipher.DECRYPT_MODE, privateKey);    
		            byte[] output= cipher.doFinal(cipherData);    
		            return output;    
		        } catch (NoSuchAlgorithmException e) {    
		            throw new Exception("无此解密算法");    
		        } catch (NoSuchPaddingException e) {    
		            e.printStackTrace();    
		            return null;    
		        }catch (InvalidKeyException e) {    
		            throw new Exception("解密私钥非法,请检查");    
		        } catch (IllegalBlockSizeException e) {    
		            throw new Exception("密文长度非法");    
		        } catch (BadPaddingException e) {    
		            throw new Exception("密文数据已损坏");    
		        }           
		    }    
		    
		        
		    /**  
		     * 字节数据转十六进制字符串  
		     * @param data 输入数据  
		     * @return 十六进制内容  
		     */    
		    public static String byteArrayToString(byte[] data){    
		        StringBuilder stringBuilder= new StringBuilder();    
		        for (int i=0; i<data.length; i++){    
		            //取出字节的高四位 作为索引得到相应的十六进制标识符 注意无符号右移    
		            stringBuilder.append(HEX_CHAR[(data[i] & 0xf0)>>> 4]);    
		            //取出字节的低四位 作为索引得到相应的十六进制标识符    
		            stringBuilder.append(HEX_CHAR[(data[i] & 0x0f)]);    
		            if (i<data.length-1){    
		                stringBuilder.append(' ');    
		            }    
		        }    
		        return stringBuilder.toString();    
		    }    
		    
		    
		    public static void main(String[] args){    
		        RSAEncrypt rsaEncrypt= new RSAEncrypt();    
		        //rsaEncrypt.genKeyPair();    
		         
		    
		        //加载公钥    
		        try {    
		            rsaEncrypt.loadPublicKey(RSAEncrypt.DEFAULT_PUBLIC_KEY);    
		            System.out.println("加载公钥成功");    
		        } catch (Exception e) {    
		            System.err.println(e.getMessage());    
		            System.err.println("加载公钥失败");    
		        }    
		    
		        //加载私钥    
		        try {    
		            rsaEncrypt.loadPrivateKey(RSAEncrypt.DEFAULT_PRIVATE_KEY);    
		            System.out.println("加载私钥成功");    
		        } catch (Exception e) {    
		            System.err.println(e.getMessage());    
		            System.err.println("加载私钥失败");    
		        }    
		    
		        //测试字符串    
		        String encryptStr= "abc";    
		        System.out.println("私钥长度："+rsaEncrypt.getPrivateKey().toString().length());  
		        System.out.println("公钥长度："+rsaEncrypt.getPublicKey().toString().length());  
		        try {    
		            //加密    
		            byte[] cipher = rsaEncrypt.encrypt(rsaEncrypt.getPublicKey(), encryptStr.getBytes());    
		              
		             
		            //解密    
		            byte[] plainText = rsaEncrypt.decrypt(rsaEncrypt.getPrivateKey(), cipher);    
		  
		              
		             
		            System.out.println("密文长度:"+ cipher.length);    
		            System.out.println(RSAEncrypt.byteArrayToString(cipher));    
		            System.out.println("明文长度:"+ plainText.length);    
		            System.out.println(RSAEncrypt.byteArrayToString(plainText));    
		            System.out.println(new String(plainText));    
		        } catch (Exception e) {    
		            System.err.println(e.getMessage());    
		        }    
		    }  
}
